Power-driven type action



Oct. 10, 1950 H. c. YAEGER POWER-DRIVEN TYPE ACTION 2 Sheets-Sheet 1 Filed Sept. 12, 1947 IVENTOR. 3 HARRY QYAEGER ATTORNEY Oct. 10, 1950 H. c; YAEGER 2,525,278

v POWER-DRIVEN TYPE ACTION i iledseptl 12, 1947 2 Sheets-Sheet 2 PRINT/N6 POINT I PRINTING -POINT ANGULAR MDVEMENT OF PARTS I7 4 a" /2 l6 zoz4za POWER MOVEMENT OF PART 22 4 HARRY CYAEGEI? A TTORNE Y Patented Oct. 10, 1950 POWER-DRIVEN TYPE ACTION Harry 0. Yaeger, West Hartford, Conn., assignor to Underwood Corporation, New York, N. Y., a

corporation of Delaware Application September 12, 1947, Serial No. 773,687

12 Claims.

This invention relates generally to power-operated type actions and more particularly to type actions including such as are used for punctuation printing.

More specifically this inventionis an improvement over the mechanism disclosed in my Patent No. 2,254,764, dated September 2, 1941.

In power-driven typewriters, the typing impact of any type bar having a large type face must be sufliciently powerful to make a clear impression. Such large face type actions for that reason are iven a substantial acceleration during the power driven portion of their stroke. For types having a considerably smaller printing area, as the period, comma, colon, etc., the impact of the type bar must be relatively lighter if the paper is not to be perforated or the impresslon darker than from the larger face type.

In the structure according to said patent, the printing impact of all small face type bars is reduced in strength by shortening the powerstroke of such small face type actions with respect to the power-stroke for the large face type actions. The power-strokes given to the small face type bars, in accordance with the structure disclosed in said prior patent, are held relatively short by appropriate adjustment of power divorcing screws associated with the associated type bardriving trains. As a result, all type actions embodying small face characters, in said prior structure, are exceedingly subject to unstable influences, such as variation in friction or other changes in the resistance offered to the operation of such type actions. If, for example, a small face type action is not well lubricated it will give an impression of inferior strength. Especially also, greater or lesser ribbon vibration, as called for when typing through the medium of two different ribbon fields, has in said prior structure, a pronounced effect on the printing impact of the small face type actions, by reason of differing energies required to vibrate the ribbon to the proper ribbon fields.

Furthermore, individual relative adjustment of the power-strokes of the type actions to suit the size of the type faces will not give satisfactory results when in combination therewith there is also used a collective impression agency or control to regulate the power-strokes for all type bars. In the machine of said patent, one setting of the collective impression control might give perfectly uniform printing characteristics to all types, but in other settings the small and large type faces would give impressions of differing strength.

It is therefore an object of the present invention to provide efficient and reliable means whereby all type bars, whether of large or small type area, may be power-operated to give printin impressions of substantially uniform density and wherein the density of such impressions may be collectively varied.

It is a further object of this invention to provide, in a power-driven typewriter, simple and efficient means whereby substantially uniform density typin impressions will be obtained from all types, whether of large or small face, at each of the many possible settings of a collective control which regulates the length of the power strokes imparted to the type carrying bars.

It is also an object of this invention to accomplish the above objects in a machine similar to that of the above patent with as little modification as possible and preferably without the use of additional parts.

In the drawings:

Fig. 1 is a sectional side view of a part of the typewriter showing one of the new small face type actions and one of those used for the normal face type bars,

Fig. 2 is a side view showing thetype actions of Fig. 1 in the positions which they occupy at the time of disengagement of their actuators from a snatch roll, and

Fig. 3 is a graph showing the operating characteristics of the two type actions shown in Figures 1 and 2 for different settings of the collective impression control.

Referrin more particularly to the drawings, the type bars H are pivoted in a semi-circular array upon an arcuate Divot rod l2 fixed in a segment I3, and are guided toward a common printing point on a platen I l. For purposes of illustration, only two adjacent type bars are shown in the drawings, one of these bars carrying a large face type and the other a small face type. Each type bar ll has a downwardly and rearwardly extending arm :5 to which is connected a link IS, the forward end of each link I6 being connected to a vertical arm of either a lever l 1A or a lever I 7B. Said levers HA and HB have, respectively, motion receiving edges 29 and 2| of differing characteristics, as will be pointed out later. The levers HA and NB are all pivoted on a straight rod [8 and are resiliently maintained in their rearward restored position by springs, 59 fixed to their lower ends. The levers HA and 57B are of graded lengths for connection at appropriate levels, by means of the links Hi, to the typebars H. The normal position of the levers I 1A and HE is determined by the engagement of the rear surfaces or edges 29 and 2| thereof with sub-levers 22. The sub-levers 22, preferably all alike, are pivoted on a straight rod 23, and each such sub-lever carries at its lower end an actuating puSh bar 25, pivotally connected thereto by a pivot pin 24. The rear ends of'push bars are urged upwardly and to the rear by springs 26 fixed at one end to ears 2! of the push bars 25 and at their other ends to an angle bar 28. Angle bar 28 also serves to limit the upward movement of the push bars 25 by the engagement of the upper edges of the bars 25 with its lower surface. Each push bar .25 carries a snatch pawl 29'pivoted'on a pin 30 of the push bar. The snatch pawl 29 is pro vided with a stud 3| engaging in a slot 32 of the push bar 25 to determine the limits of rotation of the pawl, and is gravitationally biased to its counter-clockwise position shown in Fi ure 1. In the normal position of the push bar 25, the snatch pawl 29 is clear of and disconnected from a snatch roll 33 which is common to all of the push bars 25 and extends transversely across the machine. The snatch roll 33 is continuously rotated in the direction of the arrow 34 by any suitable source of power. Each push bar 25 has associated therewith a key lever 35 pivoted on a rod 35, and biased to normal position as shown in Figure 1 by a spring 45. Each key lever 35 carries a link 31 which has a hook-shaped end normally overlying an ear 38 of the push bar 25.

A bar 39 underlies all of the push bars 25 and carries a plurality of screws 40 adjustable therein, each screw being directly below one of the bars 25. Bar 39 is carried on two widely spaced arms 4| which are pivotally carried on rod It, only one of the arms 4| being shown in the drawings'. The forward ends of the widely spaced arms 3| rest against cams 42, only one of the cams 42 being shown, fixedly carried on a shaft 46 which is rotatably adjustable by a finger wheel 43, to thereby swing the arms and raise or lower the bar 39. As will be brought out, the point in the stroke of any actuator bar 25 at which its associated snatch pawl 29 is freed from the commonsnatch roll 33 is regulatable through the position given the bar 39. lectively varies the impact of all the type bars upon the platen M.

In operation, depression of a key lever 35, through link 31, lowers an actuator bar 25 about its pivot 24, thereby pulling snatch pawl 29 into engagement with the constantly rotating snatch roll 33. After a limited initial rotation of the snatch pawl 29, as determined by the freedom of pin 3| in the slot 32 of bar 25, to the position shown in Figure 2, further rotation of the snatch roll 33 drives the pawl 29 and push bar 25 forwardly. The initial forward movement of actuating bar 25 moves its ear 38 from under the hook of link 3? on key lever 35. Subsequently, the snatch pawl 29 is disconnected from the snatch roll 33 by the engagement of a lower camming edge 44 of the bar 25 with the screw All] associated therewith.

Each sub-lever 22, while driven by its connected bar 25 moves at a substantially constant velocity. Each lever 22, during its forward movement, by contact with an edge 20 or 2| of its associated lever WA or I'IB, rocks such associated lever counter-clockwise, driving the. connected type bar clockwise toward the platen I4.

Such regulation col- Each bar 25 is released from the snatch roll 33, and thus the power source, by the engagement of its camming edge 44 with the underlying screw 40. By individual adjustment of the screws 49, the length of the power stroke imparted to each type bar I may be separately varied, thereby permitting an individual control over the printing impact of the type bars II. To permit a collective adjustment of the impact of all type bars II, the vertical position of bar 39 is variable by rotation of knob or finger wheel 43 acting, through cams 42, on arms 4| connected to bar 39.

In Figure 2 an actuator bar 25 is shown actuated to a point where the snatch pawl 29 is being forced out of its engagement with the snatch roll 33 by a camming action of the edge 35 of bar 25 against one of the screws 40. At the next moment the snatch pawl of the-bar 25 will be raised clear of the snatch roll 33 by the spring 26, and subsequently the actuator bar will be drawn rearwardly to its normal position against the underside of the angle bar 28. Since the associated lever I73 and its connected type bar (both shown in full line in Figure 2) have then acquired considerable momentum, these members will continue their movement toward the platen by reason of their acquired momentum. During this movement by momentum of the type action, restoring spring l9 and the inherent friction of the associated parts tend to reduce the momentum. The strength of impact of the type bar against the platen consequently depends substantially on these factors, acting from the time, of disengagement of the snatch pawl 29 from the snatch roll 33, namely, the distance the type bar has still to travel towards the printing point, during which distance it is subject to the retarding force of restoring spring I9 and the inherent friction, and the amount of momentum stored in the type bar at the time the snatch pawl is disconnected. The edge 2| of lever IIB, which lever is one belonging to a small face type bar, presents a point of contact for operation by the arm 22 which provides a substantially constant leverage condition throughout the power stroke of the actuator bar 25. In other words, the abutment contact between the arm 22 and the lever MB is devoid of any motion accelerating characteristic. It is thus evident that the speed of the lever IIB belonging to one of the small face or punctuation type actions, remains substantially constant up to the time when the pawl 29 is disconnected from snatch roll 33. The other small face of punctuation type actions, all have points of contact with related arms 22 to the same end.

In Figure 2 there is shown in dot-and-dash lines another type action embodying an edge 29 on a lever HA which lever is one belonging to a relatively large type face action. The push bar 25 associated with this type action is assumed to be power operated to the same extent as the one shown in full lines and associated with the lever NB. This movement of the actuator bar 25 for the lever I'IA will power actuate such lever HA and its associated parts to the positions indicated in dot-and-dash lines. The characteristic of the edge 29, as distinguished from that of the edge 2|, is that the point of contact between the arm 22 and the lever I'IA, moves downwardly as the push bar 25 is driven from the normal position of Figure l tothe position shown in Figure 2. This results in an increase in the effective length of the actuating arm of lever 22 and in a corresponding decrease in the effective length of the driven arm of lever HA, and thus provides.

for an acceleration of lever A during the power driven part of its movement. As may be seen in Figure 2, the difference in the contact faces and 2| provides that, for equal motions of the related actuator bars 25, the motion received by the lever I'IA will be greater than that received by lever I13, and that lever HA is, when its actuator bar is released from the snatch roll 33, moving at a higher velocity than would be a lever I'IB whose actuator bar was similarly released after the same power stroke.

Figure 3 shows graphically the effect of the differing rolling edges 2!] and 2| on the motion of levers HA and HE and their connected type bars I I. The horizontal scale is in increments of rotation of sub-lever 22, and the vertical scale is in increments of angular rotation of the levers HA and MB. The upper set of curves, identified by the character A, pertains to one of the levers l 1A, while a lower, straighter set of curves, identified by the character B, pertains to one of the levers MB. The solid line portion of each graph represents the power-driven movement which will be given the lever HA or IIB if the collective impression control mechanism is set for maximum type bar impact. The diverging dotted lines, as will be explained in greater detail, indicate the behavior of the type actions during movement by momentum for certain collective printing adjustments. It will be noted that the solid line portion of curve B is nearly straight, indicating little or no acceleration of the lever llB, while the solid line portion of curve A, by reason of its more pronounced upward curvature, indicates a continuous and increasing acceleration of the lever HA.

It will be recalled that the extent of the power strokes of the push bar 25 may be varied by adjustment of the disengaging bar 39. The efiect upon the type bar printing impact caused by a reduction of the actuator power stroke may be seen in Figure 3, where the dotted lines 20A, 24A and 28A and 20B, 24B and 28B indicate the continued movement of the levers I 1A and 11B respectively due to momentum, following disengagement of their associated actuator bars 25 from the power drive roll 33 after the three different extents of drive movement represented by vertical lines, the extent of drive movement being regulated by finger wheel 43. Following release of the push bar 25 from the snatch roll 33, the push bar is retracted by its spring 26 and exercises no furthe effect upon the levers l 1A or MB. In Figure 3 the printing points for the levers IA and WE are represented at different angular positions of these levers, this being due to the difference in lengths of these levers and the requirement that the upper ends of all levers must move a uniform distance to actuate a type bar. A comparison of the slopes of curves 20A, 24A and 28A of Figure 3 at the represented printing points indicates that the printing impact of a large face type bar is variable to a greater extent by the same collective printing regulation than is the impact of a small face type bar. This relative degree of variation is determined partly by the differing velocities attained by the type actions at the end of the power strokes of push bars 25 and partly by the distance over which the forces acting to retard the type action are effective. These factors, as has been previously described, are jointly and inversely varied by the adjustment of the collective printing control knob 43.

For a type action having a small face type bar and a lever l'lB, the maximum impact must be less than that for a large face type action. Also the change in impact due to an adjustment of the collective impression control knob 43 must be proportional to and hence smaller than the change in impact of a type bar having a large face type. As is indicated in Figure 3, the use of a lever l'iB having a driven edge 2! for small face type bars, gives to the type bar I I at the point of release of actuator bar 25 from the power roll 33, a velocity which is less than that of the large face type bars and which velocity is little altered by a change in the point of power release. As further indicated by the slope of curves 20B, 24B and 28B at the represented printing point, the printing impact of such a small face type action is only moderately variable by adjustment of the impression control knob as which determines the length of power stroke of actuator bar 25. The

' entire range of variation of printing impact for.

. point, a separate power actuator for each one of the small face type bars is due almost completely to the inherent friction and the restoring springs i9 acting over a greater or lesser portion of the type bar movement. Hence, the variation in the printing impact of the small face type bars which may be obtained by an adjustment of the collective control knob 43' is less than the variation of printing impact of the large face type bars for which the additional factor of a variable velocity at the point of release of the type action from the power drive also affects the impact variation.

It will be observed that the small type face actions of the present invention are, due to their being power actuated to within a relatively short distance of their printing positions, no longer detrimentally subject to influences, such as change in frictional conditions and resistance changes due to different extents of ribbon vibration, which influences formerly caused great fluctuations of the printing impact. It will also be understood that the printingimpact of the small face type actions is individually and finely adjustable by the power-stroke regulating-screws- 40.

It is thus evident that by the joint use of the two types of type action disclosed, the printing impressions from both large and small face type may be congruent over the entire range of adjustment of the collective impression control wheel or member 43.

What is claimed is:

1. In a typewriter, a series of type bars, some having large face and some having small face type, all mounted for movement to a printing said type bars, said power actuators being selectively operable to execute substantially equal ac-- tuating strokes, and individual means for each actuator to transmit its actuating stroke to its; associated type bar to drive it partly toward the printing point, said individual means in connection with the type bars which have large face type comprising a motion accelerating rolling connection, and said individual means in connection with the other type bars comprising motion v 7 actuatin strokes, individual means for each actuator to transmit its actuating stroke to, its associated type bar to drive it partly toward the printing point, said individual means in connection with the type bars which have large face type comprising a motion accelerating rolling connection, and said individual means in connection with the other type bars comprising motion transmitting means which are substantially devoid of any motion accelerating characteristic, and means to predetermine universally the magnitude of said actuating strokes of said power actuators whereby the impact of said large face type bars at the printing point is always greater than the impact of said small face type bars and said impacts are commonly variable.

3. In a typewriter, a series of type bars, some having large face and some having small face type, all mounted for movement to a printing point, a separate power actuator for each one of said type bars, said power actuators being selectively operable to execute substantially equal actuating strokes, and individual means for each actuator to transmit its actuating stroke to its associated type bar to drive it partly toward the printing point, said individual means in connection with the type bars which have large face type comprising two levers having motion accelerating rolling association, and said individual means in connection with the other type bars comprising two levers, one having with the other a substantially constant-leverage abutment connection.

4. In a typewriter, a series of type bars, some having large face and some having small face type, all mounted for movement to a printing point, a separate power actuator for each one of said ty'pe bars, said power actuators being selectively operable to execute substantially equal actuating strokes, individual means for each actuator to transmit its actuating stroke to its associated type bar to drive it partly toward the printing point, said individual means in connection with the'type bars which have large face'type comprising two levers having motion accelerating rolling association; and said individual means in connection with the other type bars comprising two levers, one having with the other a substantially constant-leverage abutment connection, and means to predetermine universally the magnitude of said actuating strokes of said power actuators whereby the impact of said large'face type bars at the printing point is always greater than the impact of said small face type bars and said impacts are commonly variable.

5. In a typewriter, a plurality of groups of type actions, each group comprising type carrying levers and other levers connected thereto, a power-operated member, an actuating member for each of said other levers, means for connecting each of said actuating members to said poweroperated member for a resulting power-driven stroke thereof, an operative connection having a variable actuating arm between each said other lever of a first of said groups and its associated actuating member whereby said other lever is moved with an increasing velocity during the stroke of said actuating member, and an operative connection having a substantially constant actuating arm between each said other lever of another'of said groups and its associated actuating member for driving said other lever at a substantially constant velocity.

6'. In a typewriter, a plurality of groups of type actions, each group comprising type carrying levers and other levers' connected thereto, a power-operated member, an actuating member for each of said other levers, means for connecting eachof said actuating members to said poweroperated member for a resulting power-driven stroke thereof, an operative connection having a variable actuating arm between each said other lever of a first of said groups and its" associated actuating member whereby said other lever is moved with an increasing velocity during the stroke of said actuating member, an operative connection having a substantially constant actuating arm between each said other lever of another of said groups and its associated actuating member for driving said other lever at a substantially constant velocity during said power-driven stroke and manually adjustable means cooperative with said actuating members for releasing said members from said power-operated member at a variable point, in their stroke whereby the associated type actions may be driven at velocities determined by the adjustment of said adjustable means,

'7. In a power-operated typewriter having a set of type carrying bars, operation controlling keys therefor, a power-driven, toothed rool and a set of actuating bars individually connectable by said keys to said toothed roll for a resulting powerdriven stroke thereof, a group of sub-levers, each pivotally connected to one of said actuating bars, a plurality of levers, means connecting one of said levers to each type bar, a rolling edge of substantial radius On certain of said levers, said edge bearing against an associated sub-lever at a point intermediate the pivots of said lever and sub lever, and a protuberance of relatively small radius on others of said levers, each said protuberance contacting the associated sub-lever at substantially the same point during the entire power-driven movement of said sub-lever and its connected actuating bar, whereby the first said levers are driven by their sub-levers at a constantly increasing velocity and the other said levers arev driven by their sub-levers at a substantially constant velocity.

8. In a power-operated typewriter having a platen, a set of type carrying bars for printing on a record material held against said platen, type bar operation controlling keys, a power-driven toothed roll, a set of actuating bars individually connectable under control of said keys to said toothed roll for a resulting power-driven stroke, a group of sub-levers each connected to one of said actuating bars, an adjustable bar, a camming edge on each actuating bar for contact with said adjustable bar during the power stroke of said actuating bar to effect disengagement of the latter from'said power-driven roll, means for adjustably positioning said adjustable bar to predetermined- 1y vary the duration of the power stroke of said actuating bars, a plurality of levers, means connecting each of said levers to a type bar, a rolling edge of substantial radius on certain of said levers, each rolling edge bearing on an associated sublever at a point intermediate the pivots of said lever and said sub-lever, and a protuberance of relatively small radius on others of'said levers, each said protuberance contacting its associated sub-lever at substantially the same point during the entire power-driven movement of said sub lever and its connected actuating bar, whereby each of the first said levers is driven by-its associated sub-lever at a constantly increasing velocity during the power stroke of the associated actuating bar and each of the others of said levers 9 is driven by its associated sub-lever at a substantially constant velocity during the power stroke of its associated actuating bar,

9. In a typewriter, a series of type bars, some having large face and some having small face type, all mounted for movement to a common printing point, a separate power actuator for each one of said type bars, said power actuators being selectively operable to execute actuating strokes,

and individual means for each'actuator to transmit its actuating stroke to its associated type bar to drive it partly toward said printing point, the type bars printing by force of momentum, said individual means for the type bars which have large face type comprising each a motion accelerating device, and said individual means for the type bars having small face type comprising each instead of a motion accelerating device, a motion transmitting device substantially devoid of any motion accelerating characteristic.

10. In a typewriter, a series of type bars, some having large face and some having small face type, all mounted for movement to a common printing point, a separate power actuator for each one of said type bars, said power actuators being selectively operable to execute substantially equal actuating strokes, and individual means for each actuator to transmit its actuating stroke to its associated type bar to drive it partly toward said printing point, the type bars printing by force of momentum, said individual means for the type, bars which have large face type comprising each a motion accelerating device, and said individual means for the type bars having small face type I comprising each instead of a motion accelerating device, a motion transmitting device substantially devoid of any motion accelerating characteristic, the two kinds of said devices being proportioned relatively to each other for power-driven movement of the small face type bars toward the printing point to an appreciably less extent than the large face type bars.

11. In a typewriter, a series of type bars, some having large face and some having small face type, all mounted for movement to a common printing point, a separate power actuator for each one of said type bars, said power actuators being selectively operable to execute substantially equal actuating strokes, individual means for each actuator to transmit its actuating stroke to its associated type bar to drive it partly toward said printing point, the type bars printing by force of momentum, said individual means for the type bars which have large face type comprising each a motion accelerating device, and said individual means for the type bars having small face type comprising each instead of a motion accelerating device, a motion transmitting device substantially devoid of any motion accelerating characteristic, and means to predetermine universally the magnitude of said actuating strokes of said power actuators whereby the impact of said large face type bars at the printing point is always greater than the impact of said small face type bars and said impacts are commonly variable.

v 12. In a typewriter, a series of type bars, some having large face and some having small face type, all mounted for movement to a common printing point, a separate power actuator for each one of said type bars, said power actuators being selectively operable to execute substantially equal actuating strokes, individual means for each actuator to transmit its actuating stroke to its associated type bar to drive it partly toward said printing point, the type bars printing by force of momentum, said individual means for the type bars which have large face type comprising each a motion accelerating device, and said individual means for the type bars having small face type comprising each instead of a motion accelerating device, a motion transmitting device substantially devoid of any motion accelerating characteristic, the two kinds of said devices being proportioned relatively to each other for power-driven movement of the small face type bars appreciably less toward the printing point than the large face type bars, and means to predetermine universally the magnitude of said actuating strokes of said power actuators whereby the impact of said large face type bars at the printing point is always greater than the impact of said small face type bars and said impacts are commonly variable.

HARRY C. YAEGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,827,693 Von Reppert Oct, 13, 1931 2,217,179 Mills Oct. 28, 1940 2,254,764 Yaeger Sept. 2, 1941, 

